Berberine suppressed epithelial mesenchymal transition through cross-talk regulation of PI3K/AKT and RARα/RARβ in melanoma cells

Berberine is a natural compound extracted from Coptidis rhizoma, and accumulating proof has shown its potent anti-tumor properties with diverse action on melanoma cells, including inhibiting cancer viability, blocking cell cycle and migration. However, the mechanisms of berberine have not been fully clarified. In this study, we identified that berberine reduced the migration and invasion capacities of B16 cells, and notably altered pluripotency of epithelial to mesenchymal transition associated factors. We found that berberine also downregulation the expression level of p-PI3K, p-ART and retinoic acid receptor a (RAR alpha) and upregulation the expression level of retinoic acid receptor beta and gamma (RAR beta and RAR gamma). These effects of PI3 kinase inhibitor LY294002 treatment mimicked Berberine treatment except the expression level of RAR gamma. Moreover, Western blot analysis showed that the decreased PI3K and ART phosphorylation, increased the epithelial maker E-cadherin, and upregulation level of RAR beta while decreased the mesenchymal markers N-cadherin and downregulation level of RAR alpha by incubation with LY294002 in mouse melanoma B16 cells. In conclusion, Our study reveal that berberine can reverse the epithelial to mesenchymal transition of mouse melanoma B16 cells and may be a useful adjuvant therapeutic agent in the treatment of melanoma through the PI3K/Akt pathway and inactivation PI3K/AKT could regulate RAR alpha/RAR beta expression. (C) 2016 The Authors. Published by Elsevier Inc.